The eagle with extended wings as if in the act of flying, has always, from the majestic character of the bird, been deemed an emblem of imperial power
The eagle symbolized strength, courage, farsightedness, and immortality. It is considered to be the king of the air and the messenger of the highest Gods. Mythologically, it is connected by the Greeks with the God Zeus, by the Romans with Jupiter, by the Germanic tribes with Odin who shapeshifted into an eagle, and with the Druids as a symbol of the Supreme God ..
By the Judeo-Christian scriptures with God, and in Christian art with Saint John the Evangelist.
The Eagle was an ensign of the ancient kings of Persia.
It was a bird sacred to the Sun in Egypt, and in Greece it was the emblem of Jupiter.
Marius, the Consul of Rome, 102 B. C., ordained that the Eagle should be the sole designation of the legions as their ensign, and allowed other emblems to designate the cohorts. The single headed Eagle thereby became the emblem of the imperial power of Rome ever afterwards.
After the division of the Roman Empire into the East and the West, the emperors of the West used a black Eagle, and those of the East a golden one, since which period Austria, Prussia, Russia, France, and also Poland, when a nation, have also used the Eagle as their royal emblem.
The double headed Eagle signifies a double imperial power, and was for the use of emperors who claim to be the successor of the Caesars of Rome ; Thus the Eagle of the Eastern Empire united with that of the West, typifying the Holy Roman Empire, and is where we see the use of this double head.
Charlemagne was the first to make use of the double headed eagle when he became the head of the whole German Empire by adding the second head A. D. 802, thereby denoting the union of Rome and Germany.
After the dissolution of the Holy Roman Empire in 1806, the double-headed eagle was retained by the Austrian Empire, and served also as the coat of arms of the German Confederation.
The symbol of the double headed Eagle was first known to Masonry in 1758, upon the establishment of a body calling itself Emperors of the East and West.
Eagle and Double Headed Eagle Symbolism in Freemasonry. As a symbol the Eagle more prominently appears in the 18th, 30th, 32nd and 33rd degrees, the first being an Eagle of one head, and the others double headed.
The double headed Eagle of Kadosh, that is of the 30th, 31st and 32d degrees, is a white and black Eagle. The head, neck, legs, and tips of the wings are of white feathers, while the body and wings are black. In brief, the bird should be in its natural colors, its wings extended yet drooping. The black symbolizing decay and the white sublimation, or the approching gradual change to the incorruptible, the becoming pure, holy, Kadosh, immortal. In the claws is a naked sword; one talon of the right claw clinching the hilt of the steel blade of serpentine shape, the left claw grasping the blade. The white ribboned motto pendent from the hilt to the point of the sword contains the words " Spes Mea in Deo Est" in black.